Endothelin, having potent vasoconstrictive effect, blood pressure elevating effect, and cell proliferation effect, is considered to be a substance that contributes to various diseases and disorders including heart diseases such as ischemic heart infarction, congestive heart failure, arrhythmia, and unstable angina; airway diseases such as asthma; hypertonia such as pulmonary hypertension, renal hypertension, and hypertension accompanying organ transplantation; circulatory diseases such as subarachnoid hemorrhage and post-PTCA reconstriction or vasospasm; kidney diseases such as acute and chronic renal failure; diabetes, hyperlipemia, and other diseases that are accompanied by vascular lesion, as well as arteriosclerosis; liver diseases such as alcohol-induced liver disorders; gastrointestinal disorders such as those of gastric mucosa; bone diseases; prostatic hypertrophy and urinary disorders; cancer; and skin diseases concurrent with proliferation of melanocytes [Saishin-Igaku (may be translated to "Medicine Up-to-date"), 94, 335-431(1994), Igaku-no-Ayumi (may be translated to "Progress of Medicine"), 168, 675-692(1994), Igaku-no-Ayumi, 170, 357(1994), Pharmac. Rev., 46, 325(1994), and Gendai-Iryo (may be translated to "Modern Remedies"), 27, 1 (1995)].
It has come to be elucidated that a variety of actions of endothelin are triggered upon binding of endothelin to its receptors in organs of the body, and that the vasoconstriction caused by endothelin is induced by the mediation of at least two different receptors (ET.sub.A receptor and ET.sub.B receptor). Therefore, a compound that prevents endothelin from binding to these two receptors should be useful as a preventive and therapeutic agent for the above-mentioned diseases in which endothelin participates. Heretofore, a number of compounds have been reported as exhibiting endothelin antagonism [J. Med. Chem., 36, 2585 (1993), Nature, 365, 759(1993), Circulation, 88, 1-316 (1994), Saishin-Igaku, 94, 424-431(1994), J. Med. Chem. 37, 1553(1994), and Japanese Patent Application Laid-Open (kokai) No. 5-222003)].
However, there have not yet been found compounds that exhibit satisfactory endothelin antagonism.
Accordingly, the present invention is directed to the discovery of a compound that has potent endothelin antagonism, as well as to the provision of pharmaceuticals containing such a compound as the active ingredient.